[Detection of learning impairment in offspring in reproduction tests]

We examined the ability of learning and its retention employing test with the water T-maze, shuttle box and passive avoidance response (PAR) in offspring from mother rats treated with N-methylnitrosourea (MNU) or chlorpromazine (CPZ). The offspring of MNU-induced learning impairments were detected only in tests with the water T-maze and PAR. On the other hand, CPZ induced impairments were detectable only in tests with the shuttle box and PAR. Thus offspring from mother rats treated with MNU or CPZ showed partially different responses. In retention tests, both MNU and CPZ caused impaired ability in the water T-maze and PAR. In the PAR test, impairment was most clearly detectable. From these results, the PAR test appears to be the most useful method in detection of impairments in learning and retention ability, especially the latter, in the reproduction test of offspring.